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Peter Anvin" , "Mike Rapoport (Microsoft)" , Jason Gunthorpe , Lu Baolu , David Hildenbrand , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Kiryl Shutsemau , iommu@lists.linux.dev, Kevin Tian , stable@vger.kernel.org Subject: Re: [PATCH] x86/mm/pat: allocate split page tables as kernel page tables Message-Id: <20260720161728.1e5e5d848bcb53bc8757ede5@linux-foundation.org> In-Reply-To: <20260720-fix-cpa-kernel-pagetables-v1-1-0766e782cefe@kernel.org> References: <20260720-fix-cpa-kernel-pagetables-v1-1-0766e782cefe@kernel.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: E1A841C0002 X-Rspam-User: X-Stat-Signature: 7qhounoy13i36bzxjaonx5puas3bq1ex X-Rspamd-Server: rspam04 X-HE-Tag: 1784589450-188322 X-HE-Meta: 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 wqcoXMJF TQvWOA5b5bWURiptkki/EWorDdd7PsSVJwR+jrTBNBb5ps/03KOgqnxKZF10wHiOZVdj+GBGCfh9RgMqKeFmZPEUpgxokob2EgTF/s+DP4Y/3JxA8zrc5ItTSgH/4jromB0UkWJpUzRL/M+ZP+8Mfprmw5JJ9HDCdfTOYIuLCyf7qSamntj1rHCN42HMuPgTVVUoqPjp/keiUJyvwtnaWpEkVvPS1qf2xL9rEmT7DydqBcZMdAAQrfUV90KPTUeyBpc+x2HmaDZNcCgmPP5+rmgbvnm5eU67cHJG0RUqdM7QInpIwMx8EvSR52NjGsn6AQUHGI/SZ9bW2cvE= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, 20 Jul 2026 10:27:29 +0100 "Lorenzo Stoakes (ARM)" wrote: > When splitting a large page in CPA in __split_large_page() we allocate a > PTE directly without going through the standard page table allocation > routines such as pte_alloc_one_kernel(). > > This means the page table constructor is never called nor is the page table > marked as a kernel page table. Thanks, I'll await x86 review on this (Dave?). Also, Sashiko might have found a pre-existing thing: https://sashiko.dev/#/patchset/20260720-fix-cpa-kernel-pagetables-v1-1-0766e782cefe@kernel.org